Thats why I stated earlier the "steam pocket" theory is open to debate. The answer may well be, "it depends" on a number of variables. One thing is for sure, if you DO overheat, you ARE going to have steam pockets around the combustion chamber, not good.
As to "that stuff will ruin your rod bearings", so will
antifreeze. If you got a major head gasket leak you got serious trouble no matter how you cut it. You are going to loose water, it is going to overheat, you will have "steam pockets", you stand a good chance of warping your alloy head and it will contaminate your
oil. With Evans Coolant it might provide enough "cushion" during this catastrophic event to prevent "steam pockets", prevent over pressure, prevent as much coolant entering the engine
oil area and give you just a little more time to see the problem and get her shut down.
I suspect it's a wash as to whether or not Evans or
Antifreeze will or will not cause more damage in a scenario like this, it depends on the variables at the time.
This plays right into the "less pressure" is better overall line of thinking.
Remember, in my case, Pat, it's not the
antifreeze purge I'm worried about, it's only the water purge. I will likely leave no stone unturned in my efforts to get rid of all the water. Like using air pressure to blow some out as another method. Wet/Dry vac is a good call!!!!
Olddog, I suspect it takes very little over pressure from steam or air or whatever to raise the cooling system pressure beyond the cap rating and start pushing water out. Evans Coolant, no pressure!